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Get the "Current" Thread State from a Thread-local #103323

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ericsnowcurrently opened this issue Apr 6, 2023 · 2 comments
Closed

Get the "Current" Thread State from a Thread-local #103323

ericsnowcurrently opened this issue Apr 6, 2023 · 2 comments
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3.12 bugs and security fixes interpreter-core (Objects, Python, Grammar, and Parser dirs) type-feature A feature request or enhancement

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@ericsnowcurrently
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ericsnowcurrently commented Apr 6, 2023

(This is a revival of gh-84702, which @vstinner worked on several years ago.)

For a per-interpreter GIL (PEP 684) we need to start storing the "current" thread state in a thread-local variable, rather than _PyRuntime.tstate_current. There may be other benefits to the approach if we can take advantage of native compiler support (e.g. C11's __thread_local).

Also see https://discuss.python.org/t/how-to-get-the-current-thread-state/22655.

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@ericsnowcurrently ericsnowcurrently added type-feature A feature request or enhancement interpreter-core (Objects, Python, Grammar, and Parser dirs) 3.12 bugs and security fixes labels Apr 6, 2023
@ericsnowcurrently
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CC @markshannon

ericsnowcurrently added a commit that referenced this issue Apr 24, 2023
gh-103324)

We replace _PyRuntime.tstate_current with a thread-local variable. As part of this change, we add a _Py_thread_local macro in pyport.h (only for the core runtime) to smooth out the compiler differences. The main motivation here is in support of a per-interpreter GIL, but this change also provides some performance improvement opportunities.

Note that we do not provide a fallback to the thread-local, either falling back to the old tstate_current or to thread-specific storage (PyThread_tss_*()). If that proves problematic then we can circle back. I consider it unlikely, but will run the buildbots to double-check.

Also note that this does not change any of the code related to the GILState API, where it uses a thread state stored in thread-specific storage. I suspect we can combine that with _Py_tss_tstate (from here). However, that can be addressed separately and is not urgent (nor critical).

(While this change was mostly done independently, I did take some inspiration from earlier (~2020) work by @markshannon (main...markshannon:threadstate_in_tls) and @vstinner (#23976).)
carljm added a commit to carljm/cpython that referenced this issue Apr 24, 2023
* main: (53 commits)
  pythongh-102498 Clean up unused variables and imports in the email module  (python#102482)
  pythongh-99184: Bypass instance attribute access in `repr` of `weakref.ref` (python#99244)
  pythongh-99032: datetime docs: Encoding is no longer relevant (python#93365)
  pythongh-94300: Update datetime.strptime documentation (python#95318)
  pythongh-103776: Remove explicit uses of $(SHELL) from Makefile (pythonGH-103778)
  pythongh-87092: fix a few cases of incorrect error handling in compiler (python#103456)
  pythonGH-103727: Avoid advancing tokenizer too far in f-string mode (pythonGH-103775)
  Revert "Add tests for empty range equality (python#103751)" (python#103770)
  pythongh-94518: Port 23-argument `_posixsubprocess.fork_exec` to Argument Clinic (python#94519)
  pythonGH-65022: Fix description of copyreg.pickle function (python#102656)
  pythongh-103323: Get the "Current" Thread State from a Thread-Local Variable (pythongh-103324)
  pythongh-91687: modernize dataclass example typing (python#103773)
  pythongh-103746: Test `types.UnionType` and `Literal` types together (python#103747)
  pythongh-103765: Fix 'Warning: py:class reference target not found: ModuleSpec' (pythonGH-103769)
  pythongh-87452: Improve the Popen.returncode docs
  Removed unnecessary escaping of asterisks (python#103714)
  pythonGH-102973: Slim down Fedora packages in the dev container (python#103283)
  pythongh-103091: Add PyUnstable_Type_AssignVersionTag (python#103095)
  Add tests for empty range equality (python#103751)
  pythongh-103712: Increase the length of the type name in AttributeError messages (python#103713)
  ...
carljm added a commit to carljm/cpython that referenced this issue Apr 24, 2023
* superopt: (82 commits)
  pythongh-101517: fix line number propagation in code generated for except* (python#103550)
  pythongh-103780: Use patch instead of mock in asyncio unix events test (python#103782)
  pythongh-102498 Clean up unused variables and imports in the email module  (python#102482)
  pythongh-99184: Bypass instance attribute access in `repr` of `weakref.ref` (python#99244)
  pythongh-99032: datetime docs: Encoding is no longer relevant (python#93365)
  pythongh-94300: Update datetime.strptime documentation (python#95318)
  pythongh-103776: Remove explicit uses of $(SHELL) from Makefile (pythonGH-103778)
  pythongh-87092: fix a few cases of incorrect error handling in compiler (python#103456)
  pythonGH-103727: Avoid advancing tokenizer too far in f-string mode (pythonGH-103775)
  Revert "Add tests for empty range equality (python#103751)" (python#103770)
  pythongh-94518: Port 23-argument `_posixsubprocess.fork_exec` to Argument Clinic (python#94519)
  pythonGH-65022: Fix description of copyreg.pickle function (python#102656)
  pythongh-103323: Get the "Current" Thread State from a Thread-Local Variable (pythongh-103324)
  pythongh-91687: modernize dataclass example typing (python#103773)
  pythongh-103746: Test `types.UnionType` and `Literal` types together (python#103747)
  pythongh-103765: Fix 'Warning: py:class reference target not found: ModuleSpec' (pythonGH-103769)
  pythongh-87452: Improve the Popen.returncode docs
  Removed unnecessary escaping of asterisks (python#103714)
  pythonGH-102973: Slim down Fedora packages in the dev container (python#103283)
  pythongh-103091: Add PyUnstable_Type_AssignVersionTag (python#103095)
  ...
@hauntsaninja
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Looks like this was completed, thanks!

vstinner added a commit to vstinner/cpython that referenced this issue May 4, 2023
This function no longer makes sense, since its runtime parameter is
no longer used. Use directly _PyThreadState_GET() and
_PyInterpreterState_GET() instead.
vstinner added a commit to vstinner/cpython that referenced this issue May 4, 2023
This function no longer makes sense, since its runtime parameter is
no longer used. Use directly _PyThreadState_GET() and
_PyInterpreterState_GET() instead.
vstinner added a commit that referenced this issue May 4, 2023
This function no longer makes sense, since its runtime parameter is
no longer used. Use directly _PyThreadState_GET() and
_PyInterpreterState_GET() instead.
vstinner added a commit to vstinner/cpython that referenced this issue Jan 26, 2024
The current_fast_get() static inline function doesn't use its
'runtime' parameter, so just remove it.
vstinner added a commit that referenced this issue Jan 30, 2024
The current_fast_get() static inline function doesn't use its
'runtime' parameter, so just remove it.
aisk pushed a commit to aisk/cpython that referenced this issue Feb 11, 2024
…14593)

The current_fast_get() static inline function doesn't use its
'runtime' parameter, so just remove it.
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